I cant stop thinking about her

Me and my ex broke up a couple weeks ago. I was upset for a couple days then I thought I was over her, but now all I think about is her coming back to me. Near the end of our relationship she was bipolar and was depressed a lot so all my friends say its for the best to not be with her, but its all I want right now. I want more than anything for her to know how I feel but I dont want to be judged by my friends or family and I doubt she feels the same way =/